We recant the Sage Thrasher in favor of American Robin
The bird seen last Friday and reported by Glenn Kincaid and me as Sage Thrasher is most likely a young American Robin. Before we recognized that this species was 13 days earlier than any previous record, we had gone too far down the road thinking this was Sage Thrasher. See corrected checklist and pic at https://ebird.org/checklist/S72661149
Several people picked up on our error. Louis Bevier offered the best analysis and this may be helpful to others who, like us, did not check The Birds of SB County first before locking in to what turned out to be our mis-identification. Louis writes, and others add:
Why American Robin:
bill appears too long for Sage Thrasher,
white speckles mid-back are typical of retained feathers of juv. robin,
row of white dots down the outer scapulars (see https://macaulaylibrary.org/asset/33351001).
dotted pattern on the tips of the wing,
hint of tawny around the collar,
Why not a Sage Thrasher:
lacks broad white tips to tail,
not likely to perch on wires so high up.
Additionally, of the 89 records for American Robin in the SB County Breeding Bird Study, 3 records of fledglings are from mid- to late-August. That provides further support for American Robin.